The document DE 1 558 773 discloses copper alloys comprising from 10 of 12% by weight of aluminum and from 2 to 10% by weight of nickel, optionally also from 1 to 6% by weight of iron, and also a process for the heat treatment of such alloys. The heat treatment takes place in a temperature range from 427 to 566° C. Strengths of a maximum of 940 MPa were determined on specimens containing from 4 to 5% by weight of nickel and from 4 to 5% by weight of iron. DE 1 558 773 does not give any information on the electrical conductivity of these alloys.
Furthermore, corrosion-resistant copper alloys comprising from 0.1 to 11% by weight of aluminum, from 0.1 to 10% by weight of nickel, from 0.01 to 6% by weight of iron, from 0.001 to 1.0% by weight of boron and from 0.01 to 10% by weight of manganese are known from the document U.S. Pat. No. 3,901,692. Preference is given to the proportion of aluminum being from 6 to 7% by weight, the proportion of nickel being from 5 to 7% by weight, the proportion of iron being from 3 to 4% by weight and the proportion of manganese being from 5 to 10% by weight. From 0.01 to 5% by weight of cobalt can optionally be added to the alloy. An electrical conductivity in the range from 15 to 20% IACS is reported for an alloy comprising 6.5% by weight of Ni, 6% by weight of Al, 3% by weight of Co, 3% by weight of Fe and 0.2% by weight of Mn. No information in respect of the electrical conductivity is documented for cobalt-free alloys.